Dry cleaning system for garments comprising a number of wash tanks connected into independent circuits utilizing different solvents

ABSTRACT

A dry cleaning solvent wash tank comprising independent circuits utilizing different solvents of different boiling points wherein the heat input for lower boiling solvent recovery by distillation is partly supplied from the latent heat of condensation of a higher boiling solvent and wherein part of the heat of condensation serves to preheat the air introduced into the drums of the washing and drying cycle of the lower boiling solvent to aid in drying the garments so treated.

United States Patent 1 1 Zucchini [54] DRY CLEANING SYSTEM FOR GARMENTS COMPRISING A NUMBER OF WASH TANKS CONNECTED INTO INDEPENDENT CIRCUITS UTILIZING DIFFERENT SOLVENTS [75] Inventor: Guido Zucchini, Castelma g giore,

Italy 73 Assignees A.M.A. Am'gianYWMcaniGf' Associati) Societa di Fatto, Bologna, Italy [22] Filed: Oct. 1, I971 [21] Appl. No.: 185,739

[30] Foreign Application Priority Data Oct. 16, 1970 Italy .3589 A/70 ['52] US. Cl ..68/l8 C, 68/27, 202/172, 203/27 [51] Int. Cl ..D06t 43/04, D06f 43/08 [58] Field of Search ..68/18 R, 18 C, 18 F, 27', 203/27; 202/172 [5 6] References Cited 1 Jan.23, 1973 UNITED STATES PATENTS 7/1966 Halbritter ..203/27X 8/1971 McLagan ..68/18C FOREIGN PATENTS OR APPLICATIONS 886,128 1/1962 Great Britain ..68/18 R Primary Examiner-William 1. Price Assistant Examiner-Philip R. Coe Attorney-Abraham A. Saffitz [57] ABSTRACT A dry cleaning solvent wash tank comprising independent circuits utilizing different solvents of different boiling points wherein the heat input for lower boiling solvent recovery by distillation is partly supplied from the latent heat of condensation of a higher boiling solvent and wherein part of the heat of condensation serves to preheat the air introduced into the drums of the washing and drying cycle of the lower boiling solvent to aid in drying the garments so treated.

5 Claims, 1 Drawing Figure ,PATENTEDJANZIB I975 l.\'l 'EXTOR.

GU IDO ZUCCHINI DRY CLEANING SYSTEMFOR GARMENTS COMPRISING A NUMBER OF WASH TANKS CONNECTED INTO INDEPENDENT CIRCUITS UTILIZING DIFFERENT SOLVENTS The present invention relates to a dry cleaning system for garments, comprising a number of wash tanks connected into independent circuits utilizing different solvents. More particularly, the heat input for a lower boiling solvent recovery by distillation is partly supplied from the latent heat of condensation of a higher boiling solvent and part of the heat of condensation serves to preheat the air introduced into the lower boiling solvent tank to aid in drying the garments being treated.

In the field of dry cleaning machines for garments, the filtering and distilling of the solvent in order to separate if from the impurities collected during the working cycle are particularly troublesome problems.

It is expensive, time consuming and generally polluting to the atmosphere to evaporate the solvent, particularly in continuous solvent distillation equipment.

The main object of the present invention is to make available a solvent recovery working cycle which eliminates or minimizes these disadvantages in a system which is of high capacity and which attains the desired object by essentially simple means.

A further object of the present invention is to make available in a single system a plurality of wash tanks operating in separate solvent circuits which exploits the latent heat of condensation of one solvent in order to regenerate the solvent which is used in another solvent circuit, thereby effecting energy savings.

A further object of the invention is to provide a dry cleaning system utilizing different solvents, which allows each garment to be more efficiently and therefore more suitably washed in relation to the chemical characteristics of the garment fibers and the type of staining or soiling encountered.

These and other important objects are achieved by the invention in anovel system for dry cleaning garments, comprising a number of wash tanks connected into independent circuits, each of the circuits utilizing different solvents and characterized by the feature that the latent head of condensation of the solvent of one circuit is recovered and is used as the fluid means for heating the distillation still of another circuit having a lower boiling point solvent, whereby the lower boiling solvent in the other wash circuit is recovered and separated.

A further characteristic of the present invention is that the solvents utilized in the separate wash circuits must have distinctly different boiling points and that the latent heat of condensation which is not fully recovered in the still of the second circuit serves for preheating the air introduced into the drums at the end of the wash cycle for drying the garments to effect even further savings in heat energy.

A preferred embodiment of the invention is shown diagrammatically in the drawing, this embodiment utilizing a solvent washing, cleaning and recovery system which, for simplicity, has been limited to only two wash drums or tanks and which uses a different boiling solvent in one drum than in the other drum.

The drawing shows a first dry cleaning system provided with continuous distillation means and consisting the cycle.

of a wash drum 1 whose discharge port communicates with a so-called pin collecting" filter 2 which, in its turn, is connected by way of a duct 3 to the continuously operating low boiling solvent still 4.

The rectified solvent which is distilled is fed through a duct 5 to a condenser 6 and then to a collecting tank 7 for storing the rectified solvent.

The low boiling solvent used in this wash and regeneration system is thus continuously regenerated 'and returned to the recovery cycle, so that energy is recovered in the form of heat from the latent heat of condensation of the solvent.

This first low boiling solvent system is provided with a heat exchanger 8, the purpose of which is to preheat the air which is to be fed into the drum at the end of the wash cycle in order to dry the garments which are treated in the solvent cleaning system.

A second wash drum 9 for high boiling solvent is connected into the regeneration circuit of the continuously operating high boiling solvent still in series connection to the low boiling still 4 so that the heat of condensation from the high boiling point solvent augments the heat required for the solvent used in the first wash system.

In the second high boiling solvent system, the solvent leaving the drum 9 is fed to a pin collecting filter l0 and then to a continuously operating still 11 which is electrically heated by external electricity supply 12. When the solvent used in the second system has been distilled, it is fed through the duct 13 to a heat exchanger 14 which is inserted in the still 4 of the first system. In this preferred manner, the latent heat of condensation of the high boiling solvent working in the second system is thus exploited in order to boil the solvent used in the first system.

The solvent in the second system, after having given up part of its heat in the low boiling solvent sill 4, is fed to the heat exchanger 8 in order to preheat the air entering the drum 1, then into the heat exchanger 15 for preheating the air entering the drum 9.

The second solvent is then fed to a condenser 16 and then to a collecting tank 17 from which it is returned to In order to obtain high efficiency, the solvents used 7 in the two systems must have widely separated boiling points, for example, about C. in the case of perchlorethylene and about 50C. in the case of fluorocarbon l 13, a widely used low boiling dry cleaning solvent. It is contemplated that solvents other than perchlorethylene (B.P. l2lC.) can be used in the second system and that solvents other than fluorocarbon l l3 (B.P. 47C.) can be used in the first system, as long as the boiling points are separated by at least 50C.

ln summary, it is seen from the foregoing description of the preferred embodiment that the latent heat of condensation of the higher boiling solvent is used for the heat input to distill the lower boiling solvent in another regenerative washing system and this recovered latent heat is also used to preheat the-air which passes countercurrently to the solvent flow in the washing drums.

It will be understood that obvious modifications may be made to accommodate changes in the invention dictated by circumstances. For example, the heat exchangers 8, I4 and 15 may be connected into the distillation circuit of the higher boiling point solvent in different orders to accommodate for different boiling point solvents, as long as the different boiling points permit adequate heat interchange.

What is claimed is:

1. Apparatus for dry cleaning garments and for solvent regeneration comprising a plurality of wash tanks connected into at least two independent circuits, each of said independent circuits utilizing different boiling point solvents, each of said circuits including a heat exchanger and a still, said heat exchangers serving to recover the latent heat of condensation of the higher boiling solvent of one circuit by using it as the fluid means for heating the still of a lower boiling point solvent working in the other wash circuit, to thereby recover heat from the one circuit to heat and regenerate the solvent in the other circuit.

2. A dry cleaning apparatus as claimed in claim 1,

wherein a part of the latent heat of condensation of the higher boiling solvent is recycled for preheating air introduced into the wash drums at the end of a cleaning cycle to thereby aid in drying the garments.

3. A dry cleaning apparatus as claimed in claim 1, wherein the latent heat of condensation of the higher boiling point solvent is recovered by heat exchange within the still of the circuit using the lower boiling point solvent.

4. A dry cleaning apparatus as claimed in claim 3 in which the latent heat of condensation of the higher boiling point solvent is recovered by heat exchange in preheaters which supply heat to air for drying; and at the end ofa cleaning cycle in each of the two circuits.

5. A dry cleaning apparatus as claimed in claim 1, wherein the two different solvents have boiling points which are at least 50C. apart. 

2. A dry cleaning apparatus as claimed in claim 1, wherein a part of the latent heat of condensation of the higher boiling solvent is recycled for preheating air introduced into the wash drums at the end of a cleaning cycle to thereby aid in drying the garments.
 3. A dry cleaning apparatus as claimed in claim 1, wherein the latent heat of condensation of the higher boiling point solvent is recovered by heat exchange within the still of the circuit using the lower boiling point solvent.
 4. A dry cleaning apparatus as claimed in claim 3 in which the latent heat of condensation of the higher boiling point solvent is recovered by heat exchange in preheaters which supply heat to air for drying; and at the end of a cleaning cycle in each of the two circuits.
 5. A dry cleaning apparatus as claimed in claim 1, wherein the two different solvents have boiling points which are at least 50*C. apart. 